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LINQ to Entities and filling a DataGrid

58 New Member
I have asked this question previously and I had an answer that, while not exactly what I wanted and did not use a DataGridView, worked, so for that thanks Paul Johnson. However, I now need to get an answer that uses the DataGridView, since I would like to use all the cool features of the DataGridView, and also be more elegant.

The scenario is as follows... I wish to selectively read a number of records from a SQL database from a C# program using LINQ to Entities, e.g., everybody whose name is Smith. I now want to populate a DataGridView with all the "Smith's" data, i.e., first name, address details etc. Now because Smith is such a common name there could be dozens of records, and the DataGridView gives me the opportunity to scroll through the list and select the one I want.

I'm sure it can be done; I just don't know how...Anyone?
Sep 4 '11
23 9963
Joe Campanini
58 New Member
Arie, just wanted to thank you for all your help, my dataGridView window is looking so slick and in no small portion to your really, really helpful suggestions. So once again, thank you.

Joe
Nov 25 '11 #11
arie
64 New Member
No problem :) I'm glad I could help
Nov 25 '11 #12
Joe Campanini
58 New Member
Hi Arie, you are probable going to think me a bit of a twit, but how do I clear out the dataGridView? When I do a second search, without leaving the program, the next set of data gets added to the end of the previous set of data, and so on, ad infinitum!!
Nov 25 '11 #13
arie
64 New Member
Try doing this
Expand|Select|Wrap|Line Numbers
  1. CurrencyManager cm = (CurrencyManager)this.dataGridView1.BindingContext[myBindedDataSource];
  2. if (cm != null)
  3. {
  4.    cm.Refresh();
  5. }
after reloading your data source
Nov 25 '11 #14
Joe Campanini
58 New Member
Hey, I worked it out, set the bindingList to null!! Duh!!
Nov 25 '11 #15
Joe Campanini
58 New Member
Ah! Great minds think alike :-)
Nov 25 '11 #16
Joe Campanini
58 New Member
It's me again Arie. Sorry to trouble you again but I have a question that maybe you could answer. I want to expand my LINQ to SQL to include more than one "where". e.g. var q1 = from d in mdc.data
where d.surName == SurName and
where d.firstName == FirstName
select d;
Can it be done with one LINQ expression or do I do the one where and then do an "if" to include the second requirement? I've opted for the "if" solution but it doesn't look very elegant.

Joe
Nov 27 '11 #17
arie
64 New Member
I think you can do:
Expand|Select|Wrap|Line Numbers
  1. var q1 = from d in mdc.data
  2.  where d.surName == SurName && d.firstName == FirstName
  3.  select d;
Nov 27 '11 #18
Joe Campanini
58 New Member
Sorry Arie, It doesn't like that, Err message - Operator '&&' cannot be applied to operands of type string and bool. I don't know if it makes any difference but SurName and FirstName are actually SurName.Text and FirstName.Text (input from a text box)! When I hover the cursor over them that both reflect type string, so I don't know where bool is coming from.
Nov 27 '11 #19
arie
64 New Member
Are you ABSOLUTELY SURE that you didn't forget '=' character somwhere here?

If I do this:
Expand|Select|Wrap|Line Numbers
  1. var q1 = from d in mdc.data
  2. where d.surName = SurName && d.firstName == FirstName
  3. select d;
I get exactly the error message that you're getting
Nov 28 '11 #20

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